This invention relates to certain activator-stabilizer precursor compounds for use in photographic materials for processing with heat. More particularly, this invention relates to such compounds wherein the acid portion of the compound is an alpha-sulfonylacetate. One aspect of the invention relates to heat developable and heat stabilizable photographic elements comprising the described alpha-sulfonylacetate compounds. Another aspect relates to photographic compositions containing these compounds. A further aspect relates to a heat activatable photographic processing composition containing the described activator-stabilizer precursors.